1. Field of the Invention
The disclosure relates to a converter and, more particularly, to a buck DC converter.
2. Description of the Related Art
In recent years, interleaved buck DC converters are developed to meet the requirement of low output current ripple. The interleaved buck DC converter includes several conventional buck DC converters which are connected in parallel and output to a plurality of inductors with different phases. The conductive loss is reduced by a plurality of inductors for shunting current. Additionally, the output ripple current is lowered via the interleaved switching.
If the interleaved buck DC converter is applied in the high step-down ratio, the main disadvantage is that the active switch needs to withstand the high voltage of the input end when the active switch is turned off, and thus high voltage-resisting switch components should be chosen. In addition, since the step-down ratio of the interleaved buck DC converter buck is not high enough, the duty cycle of the active switch needs to operate at the critical situation of 0%. Consequentially, the additional switching loss of the active switch in the interleaved buck DC converter is generated, and the current conductive loss at the low-side switch is increased.
In addition, in order to reduce the conductive loss of each inductor, the interleaved buck DC converter should make the inductive current on each phase current average. Thus, a current control circuit should be added to each phase circuit, which makes the circuit complex and increase the cost of the components.